AM79C978 Advanced Micro Devices, AM79C978 Datasheet - Page 88

• Manufacturer Part Number: AM79C978
• Description: Single-Chip 1/10 Mbps PCI Home Networking Controller
• Manufacturer: Advanced Micro Devices

Link Change Detect
Link change detect is one of wake-up events defined
by the OnNow specification. Link Change Detect mode
is set when the LCMODE bit (CSR116, bit 8) is set ei-
ther by software or loaded through the EEPROM.
When this bit is set, any change in the Link status will
cause the LCDET bit (CSR116, bit 9) to be set. When
the LCDET bit is set, the PME_STATUS bit (PMCSR
register, bit 15) will be set. If either the PME_EN bit
(PMCSR, bit 8) or the PME_EN_OVR bit (CSR116, bit
10) are set, then the PME will also be asserted.
OnNow Pattern Match Mode
In the OnNow Pattern Match Mode, the Am79C978 de-
vice compares the incoming packets with up to eight
patterns stored in the Pattern Match RAM (PMR). The
stored patterns can be compared with part or all of in-
88
MPPEN
PG
MPMODE
MPEN
LCMODE
Link Change
Pattern
Input
BCR47
Pattern Match RAM (PMR)
BCR46
H_RESET
Figure 46. OnNow Functional Diagram
Magic Packet
Pattern Match
Link Change
MPDETECT
BCR45
Am79C978
R
S
POR
SET
CLR
POR
Q
Q
coming packets, depending on the pattern length and
the way the PMR is programmed. When a pattern
match has been detected, then PMAT bit (CSR116, bit
7) is set. The setting of the PMAT bit causes the
PME_STATUS bit (PMCSR, bit 15) to be set, which in
turn will assert the PME pin if the PME_EN bit
(PMCSR, bit 8) is set.
Pattern Match RAM (PMR)
PMR is organized as an array of 64 words by 40 bits as
shown in Figure 47. The PMR is programmed indirectly
through BCRs 45, 46, and 47. When BCR45 is written
and the PMAT_MODE bit (BCR45, bit 7) is set to 1,
Pattern Match logic is enabled. No bus accesses into
the PMR are possible when the PMAT_MODE bit is
set, and BCR46, BCR47, and all other bits in BCR45
are ignored. When PMAT_MODE is set, a read of
B C R 4 5 r e t u r n s a l l b i t s u n d e f i n e d e x c e p t f o r
S
R
R
R
S
S
POR
SET
CLR
SET
CLR
SET
CLR
Q
Q
Q
Q
Q
Q
MPMAT
LCDET
PMAT
PME_EN_OVR
LCEVENT
MPMAT
PME_EN
PME Status
POR
R
S
DET
CLR
Q
Q
PME_STATUS
PME
22206B-50